DemonAttack#

../../../_images/demon_attack.gif

This environment is part of the Atari environments. Please read that page first for general information.

Action Space

Discrete(6)

Observation Shape

(210, 160, 3)

Observation High

255

Observation Low

0

Import

gymnasium.make("ALE/DemonAttack-v5")

For more DemonAttack variants with different observation and action spaces, see the variants section.

Description#

You are facing waves of demons in the ice planet of Krybor. Points are accumulated by destroying demons. You begin with 3 reserve bunkers, and can increase its number (up to 6) by avoiding enemy attacks. Each attack wave you survive without any hits, grants you a new bunker. Every time an enemy hits you, a bunker is destroyed. When the last bunker falls, the next enemy hit will destroy you and the game ends.

For a more detailed documentation, see the AtariAge page

Actions#

DemonAttack has the action space Discrete(6) with the table below lists the meaning of each action’s meanings. As DemonAttack uses a reduced set of actions for v0, v4 and v5 versions of the environment. To enable all 18 possible actions that can be performed on an Atari 2600, specify full_action_space=True during initialization or by passing full_action_space=True to gymnasium.make.

Value

Meaning

Value

Meaning

Value

Meaning

0

NOOP

1

FIRE

2

RIGHT

3

LEFT

4

RIGHTFIRE

5

LEFTFIRE

Observations#

Atari environment have two possible observation types, the observation space is listed below. See variants section for the type of observation used by each environment id.

  • obs_type="rgb" -> observation_space=Box(0, 255, (210, 160, 3), np.uint8)

  • obs_type="ram" -> observation_space=Box(0, 255, (128,), np.uint8)

Additionally, obs_type="grayscale" cause the environment return a grayscale version of the rgb array for observations with the observation space being Box(0, 255, (210, 160), np.uint8)

Rewards#

Each enemy you slay gives you points. The amount of points depends on the type of demon and which wave you are in. A detailed table of scores is provided on the AtariAge page.

Variants#

DemonAttack has the following variants of the environment id which have the following differences in observation, the number of frame-skips and the repeat action probability.

Env-id

obs_type=

frameskip=

repeat_action_probability=

DemonAttack-v0

"rgb"

(2, 5)

0.25

DemonAttack-ram-v0

"ram"

(2, 5)

0.25

DemonAttack-ramDeterministic-v0

"ram"

4

0.25

DemonAttack-ramNoFrameskip-v0

"ram"

1

0.25

DemonAttackDeterministic-v0

"rgb"

4

0.25

DemonAttackNoFrameskip-v0

"rgb"

1

0.25

DemonAttack-v4

"rgb"

(2, 5)

0.0

DemonAttack-ram-v4

"ram"

(2, 5)

0.0

DemonAttack-ramDeterministic-v4

"ram"

4

0.0

DemonAttack-ramNoFrameskip-v4

"ram"

1

0.0

DemonAttackDeterministic-v4

"rgb"

4

0.0

DemonAttackNoFrameskip-v4

"rgb"

1

0.0

ALE/DemonAttack-v5

"rgb"

4

0.25

ALE/DemonAttack-ram-v5

"ram"

4

0.25

Difficulty and modes#

It is possible to specify various flavors of the environment via the keyword arguments difficulty and mode. A flavor is a combination of a game mode and a difficulty setting. The table below lists the possible difficulty and mode values along with the default values.

Available Modes

Default Mode

Available Difficulties

Default Difficulty

[1, 3, 5, 7]

1

[0, 1]

0

Version History#

A thorough discussion of the intricate differences between the versions and configurations can be found in the general article on Atari environments.

  • v5: Stickiness was added back and stochastic frameskipping was removed. The environments are now in the “ALE” namespace.

  • v4: Stickiness of actions was removed

  • v0: Initial versions release